By The Christian Post

One of the nation’s leading atheist legal groups has sent a warning to over 1,000 public school districts telling them not to take field trips to Answers in Genesis' creationist attractions in Kentucky.

The Wisconsin-based Freedom From Religion Foundation, which claims 31,000 members across the U.S., announced Tuesday that it contacted school districts in five states warning them that field trips to the Ark Encounter or the Creation Museum would be a violation of the First Amendment’s Establishment Clause.

“Public schools and public school staff may not constitutionally organize trips to the Ark Encounter or the Creation Museum or any other religious venue,” a letter from the nonprofit’s co-founders to schools reads.

Although the organization previously pressured schools not to organize field trips to either of the Answers in Genesis venues in 2016, FFRF felt the need to send the latest round of warning letters because, it says, Answers in Genesis founder Ken Ham continues “to encourage public schools to plan field trips” to the venues.

“Ham has been clear about the proselytizing nature of this park from the beginning,” the letter reads. “Though Ham asserts that the law is on his side, this is untrue. Unquestionably, any field trip facilitated by a public school to either attraction would be unconstitutional.”

Ham responded to FFRF’s announcement through a blog post in which he asserted that it's not unconstitutional for public school districts to hold field trips to the Ark Encounter and Creation Museum. He added that admission will be free of charge for any public school district that plans to take students on a field trip to the Ark Encounter or Creation Museum.

“As leading civil rights attorneys will tell you," Ham continued, "if classes tour the Ark or museum in an objective fashion to supplement the teaching of world religions, literature, interpretation of history, etc., the field trip is an educational experience. Now, if students were brought to the Ark or museum and told by their teacher that the religious content should be accepted as truth, then we would acknowledge that the Establishment Clause of the Constitution, as currently being interpreted by the courts, would be violated.”

Opened in 2007, the Creation Museum in Petersburg is tailored toward a Young Earth Creationist explanation of the universe. Opened in 2016, the Ark Encounter in Williamstown is a creationist theme park that features a large representation of Noah’s Ark from the book of Genesis.

FFRF's letter also cites the 1971 Supreme Court ruling of Lemon v. Kurtzmanin which the court held that schools must ensure that their programs “do not inculcate religion.” Specifically, the court ruled in that case that it's unconstitutional for a state to reimburse private schools for teachers' salaries.

“Taking public school students to a site whose self-professed goal is to convert children to a particular religion and undermine what is taught in public school science and history classrooms would be inappropriate,” the atheist group's letter further argues. “Public schools may not advance or promote religion.”

The letter also argues that Ham has in the past admitted that Answers in Genesis' parks have an evangelistic motive. FFRF points to an open letter Ham released before the opening of the Ark Encounter in 2016.